Investigating Total Petroleum Hydrocarbon (TPH) Level in the Gills, Tissues and Carapace of Blue Crab (Callinectes sapidus): A Study in the New Calabar River, Choba, Rivers State, Nigeria

Abstract

This study investigated the total petroleum hydrocarbon (TPH) concentrations in the gills, tissues, and carapace of Callinectes sapidus collected from three stations (Choba, Rumualogu and Ozuoba) along the Choba axis of the New Calabar River. Results reveal distinct spatial and temporal patterns in TPH distribution. Spatially, gill TPH levels ranged from 4.3 to 4.6 mg/kg, showing no significant differences among stations (p > 0.05). Tissues exhibited slightly higher concentrations (5.6 to 5.8 mg/kg) with significant variation between specific stations (p < 0.05), while carapace concentrations were the highest (9.1 to 9.4 mg/kg) but also stable across locations (p > 0.05). These findings indicate that tissue concentrations may be more indicative of exposure levels. Comparisons with existing literature highlight variations in TPH levels among different marine organisms, with our results aligning with studies indicating lower concentrations in exoskeletal structures. Temporal analysis across June to August showed stable TPH levels (gills: 4.5 mg/kg; tissues: 5.7 mg/kg; carapace: 9.3 mg/kg) without significant monthly variation (p > 0.05). This consistency suggests that environmental conditions and TPH sources remained relatively unchanged during the study period. Overall, while gills and tissues remained within WHO recommended limits for safe consumption; caution is warranted regarding the carapace. Elevated levels may indicate potential bioaccumulation and associated ecological and health risks.